The utterly bizarre true-life inspiration for World War II movie Operation Mincemeat

On April 30, 1943, a sardine fisherman named José Antonio Rey María found the corpse of a man floating in the sea off the coast of Spain. Documents on the body identified the deceased as Major William Martin, who had presumably died in a plane crash. In fact, Martin was an invention and the body, which had belonged to someone else entirely, had been deposited in the water by members of a British submarine crew. Although María could not know it at the time, his discovery of these human remains was a crucial link in a complex, and bizarre, plan with the codename Operation Mincemeat. The scheme involved planting fake documents on a body in the hope they would make their way to German leader Adolph Hitler and convince him that the Allied forces were about to invade Greece and Sardinia and not Sicily, which the Allies actually were planning to attack later in the year. Incredibly, this scheme actually succeeded, probably saving thousands of lives and helping to turn the course of the war in the Allies favor. Almost seven decades on, the Netflix film Operation Mincemeat, directed by John Madden and starring Colin Firth, Matthew Macfadyen, and Kelly Macdonald, details the story behind this bizarre true-life tale.

"Operation Mincemeat was hatched by the Twenty Committee which was a unit within MI5 that was concerned with deception," says the film's screenwriter Michelle Ashford. "They came up with this plan to deceive the Germans about where the Allied forces were going to land [as they started to] try retaking Europe. The only logical choice was Sicily so they had to come up with something that would make the Germans think that in fact the Allied forces were not landing in Sicily. What they came up with is Operation Mincemeat, which involved landing a dead body with state papers off the coast of Spain and hoping the Germans would get their hands on these fake papers, that they would believe them, and it would make their attention go away from Sicily to Greece."

The idea to use a dead body to fool enemy forces in this fashion had been included in a document called The Trout Memo. This list of suggested deception ploys was issued in 1939 by Admiral John Godfrey, then Britain's director of naval intelligence, but was probably the work of his assistant Ian Fleming, the future writer of the James Bond novels.

"That was a well-read dossier in the spy community which listed all these different ways that you could trick the enemy," says Ashford. "Some are absolutely insane, and some are less insane. This idea was number 28 and actually [came from] Ian Fleming who had gotten the idea from an already existing spy novel about planting papers on a dead person."

In 1942, the idea was revived by a pair of British intelligence officers named Ewen Montagu and Charles Cholmondeley (played in the film by Firth and Macfadyen, respectively) who were charged with putting the scheme in motion. Among the many problems faced by Montagu and Cholmondeley was locating a suitable corpse before the pair ultimately found an acceptable cadaver in the remains of a recently deceased Welshman named Glyndwr Michael.

So why was it so hard to secure a dead body in London during the mayhem of World War II?

"It's a really good question, and I myself was like, what's the problem here?" says Ashford. "The funny thing is that everybody is accounted for. You couldn't just go in and take bodies. It turned out finding a body that nobody would claim, that's what was hard. One of the things that's really fascinating, and one of the reasons the story was kept hidden in files for so many years, [is] I think they felt queasy about the fact that they had appropriated a human being and used that person for a military operation. I think they all knew it was kind of crazy."

The name of the plan had a predictably gruesome origin.

"When Cholmondeley first came up with the idea he called it Operation Trojan Horse and his superior Admiral Godfrey said, 'That's a ridiculous name, everyone will know,'" explains Ashford. "So when they were dealing with the dead body they thought, oh, well, we're dealing with essentially meat, and so they called it Operation Mincemeat."

In 1953, Montagu revealed parts of the story in his bestselling book The Man Who Never Was, which was adapted into a film three years later.

"The bones of the story, if that's not a bad metaphor, did come out after the war," says historian Ben Macintyre. "It came out in a strange way, though, because Montagu's book was written under the Official Secrets Act. There was a great deal that he couldn't put in and a great deal more that he didn't actually know about how that operation had been done."

It would be decades before the full tale came to light in the form of Macintyre's 2010 book Operation Mincemeat: How a Dead Man and a Bizarre Plan Fooled the Nazis and Assured an Allied Victory.

"I couldn't have written this book if the government in the U.K. hadn't undergone a sea change in regards to official secrecy and decided in the mid-to-late '90s to start systematically releasing MI5 files," says the author. "The Mincemeat files, and I'm not exaggerating, they stand about 5 feet tall. At some points, you could piece together what happens almost minute-by-minute. And, unlike most government files, they are honest, because they were never meant to be released. So when it goes wrong, and by God it goes wrong, you can see it happening in real-time in the files."

Macintyre was also gifted a trunk full of papers about the operation by Montagu's son, Jeremy, when the author visited his house.

"That contained all the material that Montagu had effectively stolen from MI5," says Macintyre. "Montagu was a canny bird, and he'd worked out, I think, probably about halfway through the operation, that he was sitting on a goldmine. So he extracted the files, which is exactly what you're not supposed to do."

Michelle Ashford read, and loved, Macintyre's book shortly after it was published.

"I got really excited," says the screenwriter. "I'm not necessarily the person who would want to write a James Bond story, but [when] I read this, I thought, oh my God, it's like the anti-James Bond story. All the operators within this story are basically sort of nebbish intellectuals who work underground like moles and hatch these odd plots, and then send them out into the world hoping that they're going to work."

Ashford recommended the book to John Madden when the pair worked together on the pilot episode of the Showtime series Masters of Sex. According to the director, "We were on our way to a crucial meeting, and Michelle gave me the book and said, 'It's an extraordinary story, and you have to tell me whether you think it can be made into a film.'"

Madden was intrigued by the notion of turning Macintyre's book into a very different type of war movie.

"It's the nature of the story that is the attraction of it," says the director, who previously adapted Louis de Bernières' World War II-set novel Captain Corelli's Mandolin for the big screen. "It's not like I was absolutely yearning to make a Second World War story. I mean, many, many, many of those films have been made. But it's one that actually incorporates some of the qualities that a lot of those films had. It isn't a battlefield story, it isn't a corridor-of-power story, but it borrows from all of those genres. We are in the corridors of power briefly and so forth, but we're dealing with this curious tributary. That was very attractive, I think, and attractive to an audience who don't necessarily know what they're in for when they come to the film."

"I think what John and Michelle have done is extraordinary," says Macintyre, whose new book Prisoners of the Castle: An Epic Story of Survival and Escape from Colditz, the Nazis' Fortress Prison will be published in September. "They've managed to create a film that is an adventure story and a war story, but also a spy story, a romance, and also a kind of comedy. That's the real brilliance I think of this. They've managed to retain the absurd elements of this, to which the protagonists were extremely alive. They were fully aware that this was slightly ridiculous and I think [Madden and Ashford] brilliantly caught the way the mission moved from being a jape, just a bit of fun really, to something that was deadly serious and very dangerous."

"I got very teary at the end and I was shocked by that," says Ashford. "I was strangely moved by the notion of how these people had come together and worked so hard to do something heroic, but [were] completely unsung, because no one knew they had done it. If it weren't for those records being released, we still wouldn't know exactly what they did and how they did it."

Operation Mincemeat was released in U.K. cinemas last month and premieres on Netflix in the U.S. May 11. Watch the trailer below.

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